1. Field of the Invention
The present invention relates to a guidance system for agricultural implements and more particularly to such a system which precisely guides an implement having earth working tools in relation to a row of plants, or other track, the system engaging a guidance furrow substantially parallel to the row and simultaneously forming such a furrow.
2. Description of the Prior Art
A major problem in the growing of a row crop is the guidance of earth working implements along a row or rows of the crop during operations such as planting, weeding, mulching, and harvesting. The implement must be precisely guided so as to perform the desired operation without damaging the plants or seeds prior to emergence. Satisfactory guidance is particularly difficult during operations such as weeding or thinning which necessarily disturbs the earth surface adjacent to growing plants and yet must not disturb the plants themselves. Since the plants of a row crop are, of course, planted parallel to furrows in the earth surface, it is well known to attempt to guide an implement along the row by a pair of oppositely inclined wheels which engage the oppositely facing sides of a furrow or furrows.
These furrow engaging, inclined wheels provide satisfactory guidance of an agricultural implement along a row crop when the furrow is newly formed or when great accuracy is not required. However, the furrows are not primarily intended for precise guidance of implements along a row and have substantial irregularities due to clods of earth and to unavoidable movements transversely of the row by the implement which formed the furrows. The use of row crop furrows formed in a conventional manner to guide implements which work the earth closely adjacent to a crop, therefore, results in unwanted contact by the implement with the crop, often causing severe damage.
In any event, repeated working of the earth surface adjacent to furrows of a row crop and/or water running over the furrows from overhead irrigation or rainfall, result in the furrows losing their original "sine-wave" form, the furrows eventually becoming substantially obliterated and the earth surface becoming nearly planar. Such a surface does not provide guidance for the inclined wheels of an implement. As the furrows become obliterated, transverse irregularities develop or become more pronounced so that only improper, transversely wavering guidance can be derived from the furrows at the best.
Crop damage due to improper guidance of an agricultural implement along a row crop can be reduced by moving the implement relatively slowly along the row while being guided by an operator to avoid individual plants. Such slow movements, however, result in additional expense due to the time required to perform the operation. Even with the implement moving slowly, some crop damage is inevitable, even where the operator is careful and attentive.